It is difficult to blame those who have the means to escape, for doing so.

...powerful drug cartels, assisted by corrupt government officials, have generated mayhem, in many cases pushing the elite out. These migrants call themselves the faces of the country’s collateral damage, tracing their arrival to extortions, kidnappings and killings that have pushed Mexico into a wave of insecurity since 2006 or before.

This month, the nongovernmental National Citizens Observatory group released figures showing that crime-related deaths had increased 84 percent since December 2006, when President Felipe Calderón sent the military and federal police forces to attack organized crime, beginning with his home state of Michoacán. Overall, an estimated 60,000 people have been killed since then...

...The newspaper Milenio, using declassified documents obtained through Mexico’s freedom-of-information law, estimated that more than 24,000 people have gone missing since 2006... overall homicides and extortions continue to increase this year, according to the report and its director, Ricardo Sepulveda.

“The truth is we haven’t seen a reduction in crimes in general, and those are the ones that most affect the security of the country,” he said. _DallasNews

The US government allows foreign nationals to buy permanent US residency status, through something called an EB-5 Immigrant Investor Visa. By investing at least $500,000__ in a new business venture in the US, a foreign national can qualify for permanent US residency.

The result is an exodus, with echoes of the 1910 Mexican Revolution, which pushed tens of thousands of Mexicans to settle throughout the southwestern U.S. The new arrivals are investing in places such as San Diego, El Paso, San Antonio and, increasingly, Dallas, creating jobs throughout North Texas...

...Some of the new arrivals make lifelong decisions on the spot. A tire executive from San Luis Potosí, who had been followed by shady men for days, stepped on the gas one afternoon and didn’t stop until he crossed into Texas. He now lives in Dallas. He spoke on condition of anonymity because he continues to cross the border, attending to business and keeping a low profile.

...
Leticia Sañudo sits outside her establishment — La Paloma Taquería — next to the Neiman Marcus department store at NorthPark Center and marvels at her good fortune. She left behind a life of privilege in Mexico City, traded everything she knew to come to Dallas with her three boys. And things couldn’t be better....

...Sañudo isn’t sure she’ll ever return to Mexico. In 2005, she feared being kidnapped and saw no future for her boys. Through a friend she met Ramírez and offered to invest in some of his eight taco restaurants. She took her savings and bought into Ramírez’s La Paloma Taquería. She is helping create jobs and introducing authentic tacos to Dallas’ upper echelons who shop next door. _DallasNews

Note in the article linked above that Mexican kidnappings are officially understated, and that Mexico could easily rank at the top of the list instead of #8.

The numbers for all of the third world countries above are likely to be understated, given the turbulent nature of the societies, the rampant corruption and incompetence in security forces, and the general "cheapness" of human life across the regions involved.